Ok so recently I received my SN75441ONE h-bridge chip (http://html.alldatasheet.com/html-pdf/28616/TI/SN754410NE/24/1/SN754410NE.html) and so begun to immanently play with it. At first I wired it to my Arduino and powered a small motor off it using the Arduinos +5v, then I added to small motors and they worked fine. Then I added 2 push buttons and some more complicated code as shown below:

This code is made so that when one of the push buttons in pressed both motors drive forward, when the other is pushed they both drive backwards and finally if are both pushed then one motor drives forward and the other backwards. I uploaded the code and added the 2 small motors and it all went well now being externally powered with a +9v battery. Anyways I decided the motors where not powerful enough for what I wanted so I took 2 out an old R/C car which was powered by 5 AA batteries. I simply replaced the older smaller motors with the new bigger ones and added another +9v battery in serial to get 12v as shown in my picture.

My problem is that the motors no longer run unless spun at first by hand, also the left seems to run better than the right? Could somebody please tell me where I am going wrong? Amps? volts? wiring? coding?

Well I've tried it with 1 mains powered plug with a 9v and 300ma output and still had the same problem but when I'm home tomorrow I will try with 2 9v 300ma power supply's in serial if that's safe? I've never linked mains power in serial before only batteries.

I'm almost certain that my picture shows the batteries in series not parallel as the neg of one goes to the pos of the other then the spare neg and pos of the batteries goes to the breadboard? Also yea my mostake I meant 18v not 12v?

Id suggest trying just the 9v supply from the mains,the bes bet would be to try a 12v lead acid battery, that will give you plenty of amperage ad 12v should be more tha. Enough for the motors, and if they get hot, stop running them,that means 12v is too much

12V is probably a little high for the typical toy motor, especially if the ones in the diagram are any indication. 6V is probably more in the proper range. With AA cells,you can add cells in series to get the ideal voltage range.